I try not to dwell on world problems. About all I can do is advocate for love, respect and optimism on an individual level and hope that all these world problems work themselves out. How many times has the implementation of one solution opened up different unforeseen problems?
Progress was originally a good idea but it has gone on for way too long.
The problem that I think poses the greatest threat to our species right now is the problem of evolutionary mismatch. We are evolved to be warring, tribalistic, overachievers, and even though those traits have arguably made us the most successful species on the planet, they are now the ones that are promising to take us out, and we are having a hard time finding the brakes. I currently spend all of my spare time working toward a solution to that one problem, even though I totally expect it is beyond our power to correct.
Education - while all the problems listed by others are very important, I feel education is the only thing that will fix our problems.
Child abuse - educating the public of the signs, educating the victims that people do care, educating the abusers of why they do this.
Hunger - educating the world about alternative solutions like The Venus Project, educating society that we have technology that corporations hide from us behind patents, educating local people about self-sustainability as we combine 1930's experience with 2018 technologies.
Religion - educating yourself on the history/theology of your religion, studying others without bias, educating yourself on philosophy, logical reasoning, and how to ask questions.
Make Trump go away
In 2 years from now, let's make that happen. In 2 weeks, let's get the ball rolling!